After mulling over things, Ash decided to swap two Pokemon in his team.
One was his Zigzagoon. Ash wanted his Loudred on the team because of how strong it was. With Loudred on the team, the other Pokemon would also push themselves to get stronger as well (none of them dared to spar with Blastoise since he was much too overpowered compared to the rest).
The other was his Sharpedo. The Pokemon refused to listen to him no matter what Ash tried and always tried attacking him or the other two, so he sent the Pokemon to Professor Oak's Lab for his and the group's safety. Ash did not bring another Pokemon on the team to replace his Sharpedo.
With the five on the team, Ash continued his training for the Dewford Gym, unwilling to even think about how easy the Gym would be if he used Blastoise. He still remembered the rude awakening he received in Johto, he was not underestimating the Gym Leaders again.
Wally, the kid Ash saved from the Corphish stuck with them a while before he continued his journey. He was just exploring Hoenn with his Ralts, with no specific aim or anything pushing him forward. Ash did not understand it. How can a person be driven if he has no goal? He didn't ask Wally that though. The boy was sensitive and the last thing Ash wanted was to upset him.
It was Wally who pointed out to Ash and Co about a little island up ahead that they could visit. The four go there and find a small 'village' of Mudkip, looked over by a man and a Mudkip. The Mudkip was a wild one that looked after the hatchlings. The man feared that once the hatchlings get sent to Professor Birch for starting trainers, the Mudkip would become lonely and sad (that was what the man was doing, hatching Mudkip for the Pokemon League for new Trainers).
The Mudkip reminded Ash of his Bulbasaur, the one who took care of the village of abandoned Pokemon in Kanto. That memory and story helped Mudkip warm up to Ash. The two spent time around the baby Mudkip together and right as Ash and Co were about to leave, Mudkip asked to join Ash's team.
With a new Pokemon on the team, Ash thought of new ways to train for the Gym Battle against Brawly. It was during this training at the beach that the group (minus Wally who left after the Mudkip village) ran into Professor Birch. Excited to see them again, the Professor almost begged them to see their Pokemon (unnecessary considering the trio would have shown him their Pokemon anyway).
Professor Birch marvelled at their Pokemon, growing excited seeing even Max was on his journey with his own Pokemon (as it turned out the Professor had asked his friend Norman to send both his children to get a Pokemon). The Professor's excitement only grew when Mays Wurmple evolved right in front of him into a Silcoon.
The Professor invites the trio to join him in his research in the nearby forest, where the four of them run into a trio of Seedot in distress. Max tries to approach but the three recoil. Professor Birch points out how to befriend the Seedot and Max follows the man's example.
The four discover that the Seedot are not able to find a suitable tree to latch on to (they rely on nutrients from trees to grow), so they decide to help the four. Professor Birch carried two while Max carried one. It took them a while but they were finally able to find a tree the Seedot liked. Two of them latched on happily while the third latched onto Max. Max decided to capture the Seedot, adding a new Pokemon to his team.
The trio part ways with Professor Birch after that and returns to the Granite Cave after the Professor points out an abandoned mine shaft they might be interested in looking into. Nothing too exciting happens there, other than May running into a Sableye that she attempts to catch but fails.
The following day the trio does not have the opportunity to train because of a passing storm.
The day after, Ash decided he had trained enough and it was time to challenge the Gym.
The Dewford Gym was constructed like a Gym more than a dojo like Cyanwood's Gym had been. The trio watched humans and Pokemon lift weights, do pushups and various other exercises. A girl and her Meditite notice the three and rush over to them.
"Here to subscribe to a Gym Membership? Though the kid's too young for one" the girl said with a bright smile.
"I'm actually here for a Gym Battle" Ash said with a smile, while May was holding Max back from attacking the girl.
The girl's face lit up.
"Right this way!"
The trio followed the girl and her Meditite, May pulling Max by the ear for being a brat. Brawly was lifting weights then the four of them entered the 'battle room' as the girl called it.
"Challengers!" the girl chirped.
Brawly dropped the weights and turned, grinning welcomingly. But with how tall the man was, and how muscled he was, the grin came off threateningly.
"Well, let's get on with it!" Brawly exclaimed, his voice far too high for someone who looks like him.
May and Max tried not to laugh.
Ash meanwhile was focused on the battle.
The battle would be a two-on-two battle royale, a format Ash was half familiar with from his battle in the Orange League. Both trainers would send both their Pokemon out at the same time and the last one standing would be victorious. Brawly sent out a Machop and the Pokemon Ash saw on his way arriving at Dewford, a Hariyama. Ash sent out his Blastoise and Taillow.
The Battle began with Machop rushing in with Karate Chop. Blastoise stood guard with Protect, while Taillow swooped in with a Wing Attack after Machop crashed into Blastoise. But Machop rolled back from the hit, reducing the damage he took from the move. Hariyama stomped over with glowing palms and Blastoise used Hydro Pump at it. Hariyama slammed its palm furiously against the water as it charged, but Taillow swooped in before it could attack Blastoise, using Wing Attack on its leg to make it stumble. Machop dived in to get a hold of Taillow, but a Quick Attack allowed Taillow to escape.
Blastoise fired an Ice Beam and Hariyama punched the beam with a flaming fist before getting up and charging again. Blastoise withdrew into his shell, canons and all and used the old spinning Hydro Pump tactic. Taillow stayed up in the air while Hariyama and Machop struggled against the consecutive waves from Blastoise. The bird Pokemon dived in at last, flying just above the water and moving with it to land Wing Attacks on both Pokemon continuously.
Until Hariyama planted its foot down and slammed an electrified fist into Taillow, knocking him out.
Blastoise stopped his spinning and planted itself before firing a Hydro Pump at the ground, creating a Tidal Wave like wave that swept both of Brawly's Pokemon away, but only knocking Machop out.
Hairyama slammed its palms on the ground and shot towards Blastoise, which Blastoise blocked with Protect before firing an Ice Beam from point blank. Hariyama flew back but planted its feet at the last moment and forced itself to halt, the beam hitting it directly in the face but with minimal damage.
"Thick Fat won't let you do too much there, little bro" Brawly grinned before Hariyama shot forward with its palms again.
Blastoise threw up another Protect, which faltered this time and the fighting-type Pokemon slammed into the Shell Fish Pokemon, knocking him off his feet. Hariyama slammed a few Thunder Punches into Blastoise, but Blastoise withdrew himself after and spun Hariyama off of him. Blastoise fired another spin, this time using Ice Beam instead of Hydro Pump. Hariyama did not receive much damage but the more froze its feet in place. Blastoise quickly switched to Skull Bash and Hariyama met it with Thunder Punch. The ice on its feet shattered and both Pokemon were shot back, both knocked out.
Brawly let out a high-pitched booming laugh.
"Little bro you've given me one of my best fights in a long time! The badge is yours! You deserve it!"